TRIGONOMETRICAL IDENTITIES - PART – 58

92. sin² A tan A + cos² A cot A + 2 sin A cos A

=

tan A + cot A

TRIGONOMETRICAL IDENTITIES - PART – 57

91. sin A (1 + tan A) + cos A (1 + cot A)

=

Sec A + cosec A

TRIGONOMETRICAL IDENTITIES - PART – 56

90. (1 + sec A) / sec A = [sin² A / (1 – cos A)]

TRIGONOMETRICAL IDENTITIES - PART – 55

89. [(1 + cos A)/sin A]²

=

[(1 + cos A) / (1 – cos A)]

TRIGONOMETRICAL IDENTITIES - PART – 54

88. [1 / cos A + sin A – 1] 

+ 

[1 / cos A + sin A + 1] 

= 

cosec A + sec A

TRIGONOMETRICAL IDENTITIES - PART – 53

87. [tan A + 1 / cos A]² + [tan A – 1 / cos A)]²

=

[1 + sin A / 1 – sin A]

TRIGONOMETRICAL IDENTITIES - PART – 52

86. [(1 – 2 sin²A)² / (cos⁴ A + sin⁴ A)]

=

2 cos²A – 1

TRIGONOMETRICAL IDENTITIES - PART – 51

85. [(sin A – 2 sin³A) / (2cos² A + cos A)] 

= 

tan A

TRIGONOMETRICAL IDENTITIES - PART – 50

84. [(cos³A + sin³A) / (cos A + sin A)] 

+

 [(cos³A – sin³A) / (cos A – sin A)] 

= 

2

TRIGONOMETRICAL IDENTITIES - PART – 49

83. [sin A – sin B / cos A + cos B] 

+

[cos A + cos B / sin A + sin B]

= 

0